Hydrocracking catalyst

ABSTRACT

Hydrocracking catalysts of improved activity comprising a Group VIB metal hydrogenation component and a crystalline aluminosilicate zeolite base are prepared by adding the Group VIB metal component to the zeolite in an aqueous acidic medium which maintains the Group VIB metal component in an essentially undissolved form. Catalysts prepared in this manner are found to display higher hydrocracking activity than conventional compositions wherein the Group VIB metal component is added to the zeolite by impregnation from an aqueous solution thereof.

United States Patent 1191 Young Jan. 14, 1975 [5 1 HYDROCRACKINGCATALYST 2,830,960 4/1958 Broomhead 252/458 x 1 Inventor: a ArthurYoung, Yorba Linda, 33231133 31323 fialifv'iid rajiijjji ii-iiiiiiiliiifi Cam 3,360,484 l2/l967 Laurent 252/455 2 [73] Assignee: UnionOil Company of California,

Los Angeles, Calif. Primary Examiner-C. Dees Attorney, Agent, orFirm-Lannas S. Henderson; [22] Flled' 1973 Richard C. Hartman; DeanSandford 21] Appl. No.1 333,848

Related U.S. Application Data ABSTRACT Division Of 2 2 1971,Hydrocracking catalysts of improved activity comprisabandonedvcommuatlon'm'pan of ing a Group VIB metal hydrogenation component and241 1969 abandongdr whch a a crystalline alumino-silicate zeolite baseare prepared iggi of Sept by adding the Group VIB metal component to thezeoabandoned.

l1te 1n an aqueous ac1d1c medium wh1ch mamtams the [52] U.S. c1. 252/455Z, 252/458 g F g 2 if 51 1111. c1 BOlj 11/40, BOlj 11/06, BOlj 11/32 t:1??- l Y f sf a??? i 58 1 16111 61 Search 252/455 2,458 ay 5? y r g aconventlonal composmons wherein the Group VlB [561 References CM 1$3631? 1 llifuilii ti n ffieii l by UNITED STATES PATENTS q 2,608,5348/1952 Fleck 252/458 x 9 Clams, N0 Drawmgs HYDROCRACKING CATALYSTRELATED APPLICATIONS This is a division, of application Ser. No.209,440, filed Dec. 17, 1971.

This application is a division of Ser. No. 209,440 filed Dec. 17, 197l,now abandoned, which in turn is a continuation-in-part of my copendingapplication Ser. No. 869,389, filed Oct. 24, 1969, now abandoned whichin turn is a continuation-in-part of copending application Ser. No.669,288 filed Sept. 20, 1967, now abandoned.

BACKGROUND AND SUMMARY OF INVENTION This invention relates to improvedhydrocracking catalysts and their preparation and to hydrocrackingprocesses employing the catalysts. Metals of Group VIB, in elementalform or in the form of their oxides or sulfides, have previously beenemployed as hydrogenation components on bases such as alumina andsilicaalumina for hydrocracking operations. More recently, crystallinezeolites have been employed as the base material for catalysts in suchreactions. While these catalysts have proved fairly satisfactory,improved performance, particularly with respect to ability to give ahigh yield of useful product, is much to be desired.

Prior art zeolite catalysts, such as those disclosed in US. Pat. No.3,013,988, comprises a crystalline aluminosilicate zeolite containing aGroup VIB metal, or oxide thereof, dispersed in the internal adsorptionarea of the zeolite. Such a dispersion was believed essential in orderto provide the catalytic material in a form having a high specificsurface suitable for catalysis. Dispersion of the catalytic material inthe inner adsorption area of the zeolite was achieved by variousprocesses such as (1) impregnation with an aqueous solution of a metalsalt, followed by drying and thermal decomposition of the metalcompound, (2) cation exchange using an aqueous solution of metal saltwherein the metal forms the cation, (3) cation exchange using an aqueoussolution of a metal compound in which the metal is in the form of acomplex cation with complexing agents such as ammonia, followed bythermal decomposition of the complex, and (4) vapor deposition of themetal or compound of the metal in the zeolite.

It has now been found that not only is dispersion in the inneradsorption area. of the zeolite not essential, but that'hydrocrackingactivity of the catalyst is greater when the hydrogenating component isincorporated in the zeolite in such a manner as to avoid impregnationinto the inner adsorption area of the zeolite crystallites or particles.Although the reason for the greater activity of the catalysts of thepresent invention is not known with certainty, it is believed that theeffect may be due to greater concentration of the hydrogenationcomponent on the exterior surface of the zeolite and, hence, its greateravailability for catalyzing the hydrocracking reaction. Also, it appearsin some cases that soluble molybdenum or tungsten compounds added to thezeolite by impregnation tend to destroy the zeolite crystal structureand acidity during the subsequent drying and calcination steps.

DETAILED DESCRIPTION According to the invention, the desired dispersionof the Group VIB metal hydrogenation component is achieved by adding itto the zeolite in a finely divided but essentially undissolvcd form. Asdisclosed in my copending parent applications cited above, this may beachieved in several ways, chiefly the following:

1. A relatively insoluble compound of the Group VIB metal may be mixedwith the zeolite in the presence of water. Examples of suitablecompounds are molybic oxide, tungsten oxide, tungstic acid, ammoniumceric dodecamolybdate, etc. The mixing may consist of-stirring, mulling,grinding, or any conventional procedure for obtaining an intimatemixture of solid materials. Mulling or grinding may be carried out inany conventional apparatus such as a pan muller, ball mill, pug mill orcone mixer for a period of time sufficient to intimately mix the GroupVIB metal compound and the zeolite and to reduce the particle size ofthe two if desired. Mulling or grinding for a period of about 10 to 30minutes with resultant reduction of average particle size to about 0.5 5microns is normally sufficient.

The optimum amount of water may vary widely, depending on the type ofmixing, the type and particle size of the Group VIB metal compound andthe zeolite, etc. Although several of these compositions, i.e., molybdicacid and tungstic acid, are fairly soluble in water, particularly atelevated pH levels, only minor amounts, i.e., less than 10 percent, aresolubilized and deposited inside the aluminosilicate unless largeamounts of water are employed, and mulling or mixing in the presence ofexcess water is continued for an extended period. Nevertheless, severalprecautions can be taken to avoid deposition of the active metals withinthe zeolite. One of these is the maintenance of a relatively low pH,preferably within the range of 3 to about 5, during the mixing in thepresence of water so as to assure the insolubility of the otherwiseslightly soluble additives.

Following the mixing, the water content of the mixture is suitablyadjusted to provide an extrudable paste, preferably in combination witha binder such as silica or alumina. The mixture is then extruded orpelleted, dried and calcined, according to conventional procedures.

2. A soluble Group VIB metal compound may be mulled or ground with thezeolite, provided the mixture is dry or contains insufficient water todissolve an appreciable amount of the soluble compound. Examples ofsuitable 'soluble compounds are ammonium heptamolybdate, ammoniumdimolybdate, ammonium paratungstate, ammonium sulfotungstate, etc.However, as in the previous case involving addition of insolublecompounds, care should be taken to assure the formation of a finelydispersed form of the calcined active metal component. All of thesoluble compounds considered in this embodiment are thermallydecomposable and become more dispersed upon calcination due tofragmentation and conversion to a different chemical form. Nevertheless,care should be taken to assure a relatively even fine particle sizedistribution of the starting materials, i.e., the ammoniumheptamolybdate, paratungstates, etc., during the mulling or mixing step.This objective can be easily accomplished by employing finely dividedstarting materials usually having particle sizes below about 300microns, preferably less than about 200 microns. The particle size ofthese materials is further reduced upon mulling and, as previouslymentioned, finer dispersion results from calcination and thermaldecomposition. Promoters or stabilizers such as nickel nitrate crystalsor cobalt carbonate may be added to the mixture prior to mulling orgrinding. Following the mulling step the mixture is treated with abinder, othercatalyst ingredients, pelleted, dried and calcined asabove. 3. Insoluble or undissolved Group VIB metal compounds can beformed in the presence of the zeolite. For example, the zeolite can beslurried in a solution of ammonium molybdate or tungstate. Then theslurry is acidified to precipitate molybdic or tungstic acid. Insolubleheteropoly compounds can also be formed in a slurry of the zeolite,e.g., by adding phosphomolybdic acid to an ammonium zeolite precipitatesammonium phosphomolybdate. Suitable insoluble combinations can also beprepared by slurrying the zeolite in an ammonium tungstate or molybdatesolution and then adding a precipitating solution which contains, e.g.,a dissolved Group IV metal (Titanium, zirconium or hafnium) compound.Solutions of the Group VIB component and the precipitating agent mayalso be added concurrently to a zeolite slurry with the initialacidities and proportions adjusted to obtain a pH sufficient to promoteprecipitation without destroying the zeolite. In addition, the Group IVmetal compound, preferably in the form of a hydrous oxide, may be addedto the zeolite prior to the addition of the Group VIB component. In anyevent, the hydrous oxides, e.g., the oxides of titanium, zirconium,thorium, iron, chromium or cerium, should have high isoelectric pointsand are preferably catalytically active alone or in combination with thezeolite or other-active constitutents. It is also presently preferredthat the pH of the media in which the Group VIB metal component is addedto the hydrous oxide-aluminosilicate system be below the isoelectricpoint of the hydrous oxide, preferably within the pH range of about 3 toabout 5.

The exact mechanism or mechanisms involved in utilizing such a Group IVmetal compound for adding the Group VIB hydrogenation component is notknown. However, it is believed that the operative mechanisms may involveeither formation of an insoluble compound with the hyd rogenatingcomponent or adsorption of the hydrogenating component as, for example,by means of ion exchange with a hydrous oxide of the Group IV metal. Inany event, utilization of the Group IV metal results in efficientremoval of the Group VIB hydrogenation component from solution and itsincorporation with the zeolite structure in such manner as to providethe described advantages.

These methods result in the nearly quantitative addition of the GroupVIB component to the zeolite since there is no appreciable loss due tounadsorbed materials. Consequently, the recovery of impregnatingsolutions is not necessitated. These methods also permit post-exchangeof stabilizing cations, such as cobalt or nickel, into the zeolite.

The mulling or grinding procedures, (1 and (2), can be followed by theaddition of an alumina so] or basic aluminum salts along with sufficientwater to form an extrudable paste. Mixtures which contain about percentalumina on a dry weight basis usually require about 50 to 60 percentwater to form an extrudable mixture. An excellent binder can be preparedby adding nitric acid to a 30 percent slurry of boehmite. Adequatepeptization occurs with 0.1 to 1.0 acid equivalents per mole of alumina.Acid-sensitive zeolites can be protected by adding a suitable buffersuch as nickel carbonate. However, the sol-zeolite mixture should bekept slightly acidic with pH less than 4.6 to avoid gelling the sol. Alow pH is also necessary to maintain insoluble molybdic or tungsticacid. Insoluble heteropoly compounds and titanium or zirconiummolybdates also decompose and dissolve in neutral mixtures.Solubilization lowers the activity and causes the catalyst to be similarto conventional impregnated preparations.

From the foregoing it will be apparent that in any of the foregoingmethods which involve the presence of a substantial aqueous phase, it isbeneficial to maintain acid conditions during the mulling and drying ofthe Group VIB-zeolite mixture. It is contemplated to maintain any pHabove the level at which destruction of the zeolite crystal structureoccurs, up to about 6. The vari ous zeolites differ considerably intheir susceptibility to acid attack, but normally pHs within the rangeof about 2-6, preferably 3-5 will be utilized. Although any compatibleacid may be used, it is preferred to employ acids having a monovalentanion, and especially acids having thermally decomposable anions such asnitric or acetic.

The crystalline zeolites employed herein, commonly known as molecularsieves, are aluminosilicates such as those of the Y, (includingultrastable Y) X, A, L, T, Q, and B crystal types, as well as zeolitesfound in nature such as for example mordenite, stilbite, heulandite,ferrite, chabazite, and the like. The preferred crystalline zeolites arethose having crystal pore diameters between about 6 15 A, wherein theSiO /Al O 'mole ratio is about 3/1 to 10/1. For most catalytic purposes,e.g., catalytic hydrocracking, it is preferable to replace most or allof the zeolitic alkali metal cations normally associated with suchzeolites with other cations, particularly hydrogen ions and/orpolyvalent metal ions such as cobalt, nickel, magnesium, zinc, rareearth metals, and the like. A particularly desirable form of zeolite isa stabilized hydrogen Y zeolite prepared by first exchanging a majorproportion of the zeolitic sodium ions with ammonium ions, thencalcining the partially exchanged material in the presence of steam attemperatures of about 700 to 1200F., then reexchanging the once-calcinedmaterial with ammonium salt to reduce the sodium content to below about0.5 weight-percent. The resulting ammonium zeolite is then mixed with ahydrous alumina binder and the desired hydrogenating metals, pelleted orextruded, and again calcined. The unit cell constant of the Y zeolitestabilized in this manner is between about 24.45 and 24.6 A.

Another particularly desirable type of zeolite for use herein isdescribed in my copending application Ser. No. 761,321. It is preparedby exchanging into a suitable zeolite, particularly Y zeolite, astabilizing proportion of a Group VIII metal, particularly nickel orcobalt, and then calcining the resulting metal zeolite prior to additionof the Group VIB metal component. Calcining the aluminosilicateintermediate the addition ofthe Group VIII and the Group VIB componentsso modifies the characteristics of the combination that the resultantcomposition exhibits activity superior to that exhibited by catalystsprepared without intervening calcination. The Group VIB metals employedherein comprise chromium, molybdenum, and tungsten or any combinationthereof, preferably molybdenum and/or tungsten, in the form of theiroxides or sulfides. Amounts of the Group VIB hydrogenation componentwill usually range from about 1 percent to 20 percent by weight of thefinal composition, based on free metal. Generally, optimum proportionswill range between about 5 percent and 15 percent. Molybdenum in theform of the sulfide is especially preferred as the hydrogenationcomponent, preferably in combination with nickelor cobalt-stabilizedzeolites.

Although as noted above, it is preferred to add the stabilizingcomponent, e.g., nickel or cobalt, to the zeolite, and calcine theresulting composition prior to addition of the Group VIB component, itis also contemplated that the stabilizing metal may be added after orsimultaneously with addition of the Group VlB component. Proportions ofthe nickel or cobalt will range from about 2 percent to percent byweight, with the preferred range being from about 4 to 8 percent. Thepartial solubility of the Group VlB component precursor in someembodiments also renders it adviasable to incorporate the stabilizingcation before adding the particulate molybdenum or tungsten compoundwith intermediate drying and/or calcination. This procedure limits lossand solubilizing of the Group VlB component.

Following incorporation of the metal constituents into the zeolite thecomposite is pelleted or otherwise treated to obtain catalyst particlesof the size and shape desired for the reaction to be catalyzed. Forhydrocracking processes, pellets of the type described in the examplesbelow are generally suitable. A binder or matrix material is desirablyincorporated in, or admixed with, the metal-zeolite composite prior topelleting in order to increase the resistance of the final catalystparticles to crushing and abrasion. Silica, introduced in the form of asol, is very satisfactory for this purpose; however, other oxides suchas alumina or mixed oxides such as silica-alumina, silica-zirconia, etc.may also be used. A particularly preferred material is Ludox silica sol,described in US. Pat. Nos. 2,574,902 and 2,597,872. Another preferredmaterial is alumina hydrogel.

The catalyst pellets are then dried and activated by calcining in anatmosphere that does not adversely affect the catalyst, such as air,nitrogen, hydrogen, helium, etc. Generally, the dried material is heatedin a stream of dry air at a temperature of from about 500 to 1500F.,preferably about 900F., for a period of about 0.5 to 16 hours,preferably about 2 hours, thereby converting the metal constitutents tooxides.

In addition, the catalysts are preferably further activated bypresulfiding with a sulfide such as hydrogen sulfide to convert themetal constituents of the catalyst to sulfides. This is readilyaccomplished, e.g., by saturating the catalyst pellets with hydrogensulfide for a period of from 1 to 4 hours. This procedure is describedin more detail in US. Pat. No. 3,239,451.

The hydrocracking feedstocks which may be treated using the catalysts ofthe invention include in general any mineral oil fraction boiling abovethe conventional gasoline range, i.e., above about 300F. and usuallyabove about 400F., and having an end-boiling-point of up to about1,000F. This includes straightrun gas oils and heavy naphthas, cokerdistillate gas oils and heavy naphthas, deasphalted crude oils, cycleoils derived from catalytic or thermal cracking operations, etc. Thesefractions may be derived from petroleum crude oils, shale oils, tar sandoils, coal hydrogenation products, etc. Feedstocks boiling above about480F., preferably between about 400 and 650F., having an API gravity of20 to 35, and containing at least about percent by volume ofacid-soluble components (aromatics olefins) are generally employed. Allof these feeds are known to contain substantial amounts of aromaticcompounds which are hydrogenated and hydrocracked only with considerabledifficulty. *As demonstrated by the examples hereinafter detailed thecatalysts of this invention are much more effective in hydrogenating andhydrocracking heavier aromatic compounds such as naphthalenes, indanes,tetralins and the like. These catalysts are therefore particularlyeffective for converting feeds containing 10 volume percent, generallyin excess of 30 volume percent of aromatics to gasoline and midba'rrelfuels.

Conversion conditions effective for promoting hydrogenation orhydrocracking generally comprise temperatures of about 5 00 to about900F., hydrogen partial pressures of about 400 3000 psig, hydrogenratios of about 1,000 to 15,000 scf/b, and liquid hourly spacevelocities ranging between about 0.5 and 5.

Whilethe foregoing description has centered mainly on hydrocrackingprocesses, the catalysts described are also useful in a great variety ofother chemical conversions, and generally, in any catalytic processrequiring a hydrogenating or acid function in the catalyst. Exam ples ofother reactions contemplated are hydrogenation, alkylation (ofisoparaffins with olefins, or of aromatics with olefins, alcohols oralkyl halides), isomerization, polymerization, reforming (hydroforming),desulfurization, denitrogenation, carbonylation, hydrodealkylation,hydration of olefins, transalkylation, etc.

The following examples will serve to more particularly illustrate thepreparation of the catalysts of the invention and their advantageousproperties in hydrocracking operations.

Examples 1-4 and Table 1 show a comparison of four catalysts withsimilar compositions and zeolitic stabilities. The conventionalpreparation of Example 1, prepared'by impregnation, had the lowesthydrogenation and hydrocracking activity. The three catalysts ofExamples 2, 3 and 4, prepared by combining insoluble forms of molybdenumwith cobalt zeolite Y, all gave similar higher hydrocracking andhydrogenation conversions, as shown in Table 1.

All four catalysts were made from the same batch of cobalt zeolite Y.The cobalt zeolite was prepared by slurrying 560 g ammonium zeolite Y in500 ml water, adding 500 ml 1.5M CoCl and heating to boiling for 1 hour.Then the slurry was filtered, washed and the exchange repeated. Afterthe second exchange the zeolite was washed free-of chloride and driedovernight at 220F. Four g portions of the cobalt zeolite were treatedaccording to Examples 14.

EXAMPLE 1 The zeolite powder was mixed with 126 ml Ludox LS 30 percentsilica sol. Then 36 ml 1.7M Co(NO was added as a coagulant. The pastewas cast into 0.094 X 0.020-inch pellets, dried at 220F. and calcined 2hours at 600F. The calcined pellets wereimmersed for 1 hour in ml of1.04M (NH MoO Then the pellets were drained, dried at 220F. andrecalcined 2 hours at 600F. Next the pellets were spread in a thin layerand the remaining drained molybdate solution was poured evenly over thepellets. The remainder of the solution was completely adsorbed. Then thepellets were redried and finally calcined at 900F.

EXAMPLE 2 The cobalt zeolite Y powder, 120 g, was dry mixed with 23.3 gmolybdic oxide for 30 minutes toa l2-inch pan muller. Then the mixturewas added to 126 ml Ludox LS and 36 ml 1.7M Co(NO and formed intopellets as in Example 1. The pellets were dried and then calcined at900F.

EXAMPLE 3 The cobalt zeolite Y powder, 120 g, was mixed with 80 ml waterand 23.3 g molybdic oxide powder. The mixture was stirred for 20 minutesand then dried overnight at 220F. The dried cake was granulated througha 60 mesh screen before mixing with 126 ml Ludox LS and 36 ml 1.7M Co(NOThe resulting paste was formed into pellets, dried, and calcined as inExamples 1 and 2.

EXAMPLE 4 Ammonium phosphomolybdate was prepared as follows: A molybdatesolution was prepared by dissolving 85.2 g (NH Mo O 4H O in 390 mlwater. Then 85 ml N HNO was added. A phosphate solution was prepared bydissolving 21.2 g (NHQ HPQ, in 85 ml water and 42 ml lSN HNO Thephosphate solution was slowly added to the molybdate solution. Then themixture was allowed to stand minutes, chilled and decanted. The pH wasadjusted to 2.0 with 3N NH OH. Then the slurry was filtered, washed withice water, and pressed out to a firm cake. The ammonium phosphomolybdatecontained 31.3 percent volatile material when a sample was calcined atl000F.

Cobalt zeolite Y, 120 g, was mixed with 76 ml water and 35.5 g of theammonium phosphomolybdate filter cake. The mixture was stirred for 20mintues and then dried overnight at 220F. The dried cake was granulatedthrough a 60 mesh screen before mixing with 126 ml Ludox LS and 36 ml1.7M Co(NO The resulting paste was formed into pellets, dried andcalcined as previously.

The feed used in the tests was a synthetic gas oil 50-50 blend oftetralin and mineral oil by volume boiling between 400 and 812F., havingan API gravity of 246 and containing 1.0 weight-percent sulfur. As themineral oil was a paraffinic stock, only 50 volume percent of the feedmolecules contained aromatic nuclei and these molecules, i.e., tetralin,were not completely aromatic. These factors tend to complicatedetermination of aromatic conversion by product analysis. The testconditions were: 650F., 1,000 psig, 2.0 LHSV and 6,000 CF H 0.

Examples 58 and Table 2 further demonstrate the adverse effect ofmolybdenum solvation on hydrocracking activity. The catalyst of Example5, made by impregnating nickel zeolite Y with a solution of ammoniumheptamolybdate, was inferior to that of Example 6, made by acidifying amolybdate solution and mixing with the zeolite. Example 8 shows theadverse effect of decomposing and dissolving ammonium phosphomolybdatein the presence of nickel zeolite Y. Higher hydrocracking conversionsand improved denitrogenation occurred when the molybdenum solubility wasdecreased through the use of ammonium phosphomolybdate (Example 7) orthe formation of molybdic acid (Example 6).

The catalysts of Examples 5-8 were all made from one batch of nickelzeolite Y. The preliminary nickel enchange consisted of mixing 550 gammonium zeolite Y (1.6% Na O) with one liter of 1.0 M nickel chloride,heating to 200F., allowing to cool, filtering and washing free ofchloride. This exchange was repeated twice. After the final wash theproduct was dried overnight at 200F. The loss on ignition was 17.6percent and the nickel content was 8.5% NiO on a calcined basis. Onehundred gram portions of this material were used to prepare the fourcatalysts of the examples. The following quantities of components wereadded to each of the catalysts:

Ammonium heptamolybdate, 26.0 g, containing 82% M003.

Ludox LS silica sol, 1 12 m, containing 0.36 g Si- Nickel oxide, 4.1 g,was added as 1.7 M nickel nitrate (0.127 g NiO/ml) or as 1.7 M nickelnitrate and nickel carbonate powder. When nickel carbonate was added thenickel nitrate was decreased to keep the same total number ofequivalents.

A small quantity of phosphorus, approximately 0.8 g P 0 was added aspart of the phosphomolybdate complex to catalysts prepared by the methodof Examples 7 and 8.

EXAMPLE 5 The nickel zeolite Y powder was mixed with the Ludox LS and 32m1 1.7M nickel nitrate. The paste was 5 cast into pellets, dried, andcalcined at 600"F. for 1 Table 1 Example 1 Example 2 Example 3 Example 4Composition v 7rMOO 14.7 12.7" 12.8 12.7" 7rCoO 5.8 5.3 5.9 5.9 7rSiO 2727 27 27 Activity Data Hours on Stream 3-19 2-18 3-19 3-19 APl 32.4 3 .837.5 35.9 400F. Conversion. vol-7r of Feed 40 53 52 51 GasolineComposition: Aromatics. VOl-% 42 36 34 36 Olcfins. vol-7v 0 0 0 0saturates. vol-7r 58 64 66 64 lmprcgnation with ammonium molybdatesolution. Muller! with insoluble molybdic oxide. Mulled with insolubleammonium phosphomolybdate.

pregnation due to nickel-ammonium exchange. After the second calcinationthe pellets were spread in a thin layer and allowed to absorb theremainder of the impregnation solution. Next, the catalyst was activatedby calcining overnight at 900F. in dry flowing air and then saturatedwith hydrogen sulfide at room temperature.

EXAMPLE 6 The ammonium heptamolybdate was dissolved in 100 ml water.Sufficient 3N nitric acid was added to lower the pH to 4.0 andprecipitate the molybdate prior of the slurry was increased from 4.9to.6.7 by addition of a small amount of ammonium hydroxide prior toevaporating on the steam bath.

The hydrocracking activity comparisons shown in Table 2 were determinedusing a gas oil feed with the following characteristics:

Gravity 249 APl Boiling Range 455-890F. Sulfur Content l.05 wt-%Nitrogen Content 0233 wt-% The test conditions were 800F., 1400 psig,2.0 LHSV, and 12,000 CF H /B.

" During molybdenum addition. Added as soluble ammonium heptamolybdate.Added as insoluble acidified molybdate.

"" Added as insoluble acidified phnsphornolybdatc. Added as solublephosphomolybdate at high pH.

to contact with the aluminosilicate. The nickel zeolite Y powder wasslurried with this solution, allowed to stand overnight, and then driedon a steam bath. The dried powder was mixed with the Ludox LS and 32 ml1.7M nickel nitrate. The paste was formed into pellets and activatedaccording to the procedure of Example 5.

EXAMPLE 7 The ammonium heptamolybdate was dissolved in 130 ml water.Then ml concentrated nitric acid was added. A phosphate solution wasprepared by dissolving 6.5 g diammonium phosphate in 25 ml water and 13ml concentrated nitric acid. The phosphate solution was slowly added tothe molybdate solution and then allowed to stand 20 minutes. Theammonium phosphomolybdate precipitate was collected by centrifuging andwashed with 50 ml water. The washed precipitate was reslurried in 80 mlwater. Powdered nickel carbonate, 2.9 g, was added as a buffer whichwould not decompose the pho'sphomolybdate complex while protecting thezeolite from strong acidity. The nickel zeolite Y powder was added tothe slurry. The pH of the combination was 4.9. Next, the slurry wasdried on a steam bath and the dried powder was mixed with the Ludox LSand 18 ml 1.7M nickel nitrate. The paste was formed into pellets andactivated according-to the previous examples.

EXAMPLE 8 The same procedure and quantities used in Example 7 wererepeated, except for the pH adjustment. The pH Examples 9 and 10 andTable 3 compare two parallel nickelmolybdena zeolite Ycatalysts. Thiscomparison again shows the favorable effect of acidifying the molybdatesolution to form relatively insoluble molybdic acid. The feed and testconditions were the same as those used in Examples 5 to 8.

EXAMPLES 9 & l0

Ammonium heptamolybdate, 20.7 g, was dissolved in ml water and the pHwas adjusted to 7.0 with lSN NH.,OH. Ammonium zeolite Y powder, 100 g,was then added and the mixture stirred and evaporated to a pastyconsistency on a steam bath. 27 ml of 1.7M nickel nitrate was added andthe mixture was stirred and dried on a steam bath. The dried materialwas then granulated and mixed with 1 l3 ml of Ludox LS and 32 ml 1.7Mnickel nitrate. This mixture was then cast into 0.094 X 0.020-inchpellets, dried and calcined at 900F. The same procedure was employed forExample 10 except that the pH was initially adjusted to 4.0 with 15N HNOAlthough lowering the pH, as illustrated in the above examples, is aneffective way of decreasing the solubility of molybdates, tungstates,etc., an even more quantitative removal from solution can be achieved byuse of an adsorbing or precipitating agent in the catalyst preparation.Insoluble hydrous oxides of metals such as titanium, zirconium, thorium,iron and chromium have been found to be particularly effective for thispurpose. The hydrous oxide, in addition to being insoluble, should havea high isoelectric point and should form a catalytically activecombination with the hydrogenation component. Addition of thehydrogenation component should be effected at a pH that is below theisoelectric point of the hydrous oxide. This pH value will generally bein the range of about 3 to 5. Examples 11-14 and Table 4 illustratepreparation and activity for catalysts using titanium or zirconium foradsorption or precipitation of molybdates into zeolite catalysts.

EXAMPLE 1 l The titania gel used in this example was prepared by adding25 ml 4M TiCl solution to 250 ml 2.4N ammonium hydroxide. The gel wascollected by filtration, washed free of chloride, and then dried for twohours at 400F. A 6.2 g portion of the dried gel was mulled with 100 gammonium zeolite Y. The mulled powder mixture was slurried in 215 ml of0.69M ammonium molybdate. The pH was adjusted to the interval 3.6 3.8with nitric acid. After two days the solids were collected byfiltration. The dissolved molybdena was recovered by evaporating thefiltrate and calcining the residue two hours at 700F. The weight of theresidue, 7.4 g, indicated that approximately 65 percent of the originalmolybdate had been adsorbed on the titania gel-zeolite mixture. Next,the recovered 7.4 g of molybdena was added back to the catalyst bymulling with the zeolite mixture. Nickel was exchanged into thiscombination by slurrying with 62 ml 1.0 M nickel nitrate, allowing tostand overnight, and filtering. The filter cake was dried, mixed with 1ml Ludox LS 30 percent silica sol and 36 ml 1.7M nickel nitrate, castinto pellets, and calcined at 900F.

EXAMPLE 12 The titania in this example was formed in situ by addingsolutions of titanium chloride and ammonium hydroxide concurrently tothe zeolite slurry. This procedure gives an improved molybdenadistribution and is easier to handle during washing. Removal of chlorideions by washing improves the subsequent adsorption of molybdic acid. ThepH must be lower than the isoelectric point of titania during theadsorption of molybdena. The specific procedure was as follows:

To 100 g of ammonium zeolite Y was added 370 ml of 0.2M TiCl, andsufficient 3N NH OH to maintain the pH.in the range 3.5 3.9. The slurrywas then filtered and the residue washed with water and slurried in 177ml of 0.69M ammonium molybdate solution. The resulting mixture was aged2 days at room temperature and filtered. The dissolved molybdena wasrecovered by evaporating the filtrate and calcining the residue 2 hoursat 700F. The weight of residue, 2.3 g, indicated that approximately 87percent of the original molybdate had been adsorbed on thetitania-zeolite combination. Next, the recovered 2.3 g of molybdena wasadded back to the catalyst by mulling with the zeolite combination.Nickel was exchanged into the catalyst by slurrying with 59 ml 1.0Mnickel nitrate, allowing to stand overnight, and filtering. The filtercake was dried, mixed with 111 ml Ludox LS and 35 ml 1.7M nickelnitrate, cast into pellets, and calcined at 900F.

EXAMPLE 13 The catalyst of this example was made by concurrently addingtitanium and molybdenum solutions to the zeolite slurry. The proportionswere adjusted during this addition to keep the pH less than 4.0 since aneutral or high pH would have caused the molybdenum to remain insolution. The specific procedure was as follows: 4

A g portion of ammonium zeolite Y was slurried in 200 ml water. Ammoniummolybdate, 177 ml 0.69M solution, and TiCl 370 ml 0.2M solution, wereadded concurrently to this slurry. Sufficient 3N ammonium hydroxide wasalso added to maintain the pH in the range 3.5 3.9. The resultingcombination was aged 2 days at room temperature and filtered. Thedissolved molybdena was recovered by evaporating the filtrate andcalcining the residue 2 hours at 700F. The weight of residue, 2.8 g,indicated that approximately 85 percent of the original molybdate hadbeen adsorbed or precipitated on the titania-zeolite combination. Next,the recovered 2.8 g of molybdena was added back to the catalyst bymulling with the zeolite combination. Nickel was exchanged into thecatalyst by slurrying with 59 ml 1.0M nickel nitrate, allowing to standovernight, and filtering. The filter cake was dried, mixed with 111 mlLudox LS and 35 ml 1.7M nickel nitrate, cast into pellets, and calcinedat 900F.

EXAMPLE 14 The catalyst of this example was made by alternate additionof titanium, molybdenum and zirconium. The final extra addition ofzirconyl chloride considerably lowered the molybdate concentration inthe filtrate (only 6.7 percent of the molybdenum remained dissolvedafter the zirconium addition). The specific procedure was as follows:

A 438 g portion of ammonium zeolite Y was slurried in 530 ml water. TiCl980 ml 0.2M solution, was added to the slurry concurrently withsufficient 3N ammonium hydroxide to maintain the pH in the range 3.53.9. The solids were collected by filtration, washed free of chlorides,and then slurried in 470 ml 0.69M ammonium molybdate. Next: ml 0.2MTiCl. and 200 m1 1.0M zirconyl chloride were added concurrently withsufficient 3N ammonium hydroxide to maintain 3.5 3.9 pH. Then thedissolved molybdena was determined by filtering, evaporating thefiltrate, and calcining the residue 2 hours at 700F. The weight of theresidue, 3.2 g indicated that approximately 93 percent of the originalmolybdate had been adsorbed or precipitated on thetitania-zirconia-zeolite combination. Next, the recovered 3.2 g ofmolybdena was added back to the catalyst by mulling with the zeolitecombination. Nickel was exchanged into the catalyst by slurrying with ml1.0M nickel nitrate, allowing to stand overnight, and filtering. Thefilter cake was dried, mixed with 295 ml Ludox LS and 93 ml 1.7M nickelnitrate, cast into pellets, and calcined at 900F.

The data in Table 4 compare the hydrocracking and hydrogenationactivities of the catalysts of Examples 1 l-l4. The feed and testconditions used in testing catalysts were the same as those used fortesting the catalysts of Examples 1 to 4. The catalyst ,of Example 14,in which the molybdenum formed the least soluble combination withtitanium and zirconium, was the most active. The catalyst of Example 13,made by concur- EXAMPLE 16 A portion of the cobalt'zeolite Y used inExample 15 was calcined l6 hours'at 900F. Then 61 g of the calcinedzeolite was mulled with 19.5 g Ni(NO '6H O rent additions, and that ofExample 12, made by ad- 5 and 18.3 g (NHUG MO7O24.4H2O Crystals in a pansorption on the in-situ titania, showed intermediate ll f 30 i Next 7 gf an i i 30 amounts of dissolved molybdena. These two catalysts Centalumina so] was added to provide 2 A1203 3 58 2:: :3:223???3532:3522?22::$2331 bingerh on ildry basis. Nitric acid in the alumina sol loweret e p o the final mixture to 3.9. The paste mixple had thelargest?IT1Ountof.dlSSlved 1O ture was extruded as one-sixteenth-inchrods. dried, num and the lowest act1v1ty. These results are consisandactivated by calcining at tent with the data in Tables 1, 2, and 3,i.e., combining or forming insoluble molybdena with the zeolite givesTable H q H H greater activity. The catalyst of Example 1, prepared byExample ls Hump lb impregnating with completely dissolved ammonium vmolybdate, was the least active catalyst tested. Mulling Activity Datawith insoluble forms of molybdenum gave appreciable F 4 Stream 5improvement, as shown by the catalysts of Examples 2, 400 c6nversi6n, v1-% of Feed 52 65 3 and 4. Forming insoluble molybdates in the presenceg zgl' lf gfifig 35 25 of the zeolite gave the highest activities, asshown by Ol fi D 0 i, the catalysts of Examples l2, l3 and l4.saturates. o 65 75 Table 4 Example ll Example 12 Example 13 Example 14Composition %M6o 12.7 11.0 10.4 9.3 %Ni0 6.5 5.8 5.9 4.0 M10, 4.5 3.33.5 4.0 42:0, 5.6 pH 3.6-3.8 3.5-3.9 3.5-3.9 3.5-3.9 Activity Data Hourson Stream 3-l9 2-18 2-]8 2-18 APl 34.7 38.5 40.3 41.2 400F. Conv., vol-kof Feed 51 59 62 73 Gasoline Comp. Aromatics, vol-76 42 3l 28 Olefins,vol-7: 0 0 0 O saturates, vol-7r 58 69 72 75 As described above, solublecomponents can be used I claim: toprepare highly active aeolitecatalysts provided there L A hydrocarbon Conversion catalyst Comprisinga fi i fiii g gg g; 3 11 2211 3 gf z g gs crystalline aluminosilicatezeolite base intimately com- 16 were made li y mulling cobalt ze lite Ygowder with posited 3 at about} 5h1eight percem of a finely divided roupV meta y rogenating component, gglz zi 2g: g rgs si z g gag 2 5612223;said hydrogenating Component or a precursor thereof alurriina sol wasadded in an amount to rbvide 2O erhavnig been composued with ald zeolite{me by CO- cent Al O binder on a y basis The pg of the mulhng the twocomponents w1th only suf f1c1ent water sion p s were 4 4 and 3 9for'Examples 15 and 16 to yield a moist, extrudable mixture in wh1ch theaquerespectively. This acidity, by forming molybdic acid, Ous i a pHbel9w about bulgsufficlcnily hlgh suppressed the tendency of molybdenumto dissolve to avold acld destruction 9 the cliysta Structure, andthereafter extrudmg the mixture into shaped The Catalyst of Example madewlth 900 Cal re ates and dr in and calcinin the resultin a cined cobaltzeolite Y, had the highest hydrocracking i y g g g g activity andproduced fewer light hydrocarbons per gr ga amount of gasoline. Resultsare shown in Table 5. The A Catalyst as defined m clam l wlllerem aquefeed and test conditions were the same as those used in Gus phase has 3PH abfmt 3 and testing h Catalysts f E l 1 to 4 3. A catalyst as definedin claim 1 wherein said zeolite base is a nickelor cobalt-stab1l1zed Yzeolite. EXAMPLE l5 4. A catalyst as defined in claim 1 wherein saidzeo- A 73 g portion of cobalt zeolite Y, which contained lite is asteam-stabilized hydrogen Y zeolite. 16.3 percent adsorbed water, was mud it g S. A catalyst as defined in claim 1 wherein said hya)' z and 13.3g 4)s 1 24' 2 rystals drogenating component is initially admixed withsaid in a pan muller for 30 minutes. Then 67 g of an acidic zeolite basein the form of molybdenum oxide and/or 30 percent alumina sol was addedto provide 20 pertungsten oxide. cent A1 0 binder on a dry basis. Nitricacid in the alu- 6, A catalyst as d fin d i l i h i id mina sol loweredthe pH of the final mixture to 4.4. The paste mixture was extruded asone-sixteenth-inch rods, dried, and activated by calcining at 900F.

drogenating component is initially admixed with said zeolite base in theform of ammonium heptamolybdate and/or ammonium phosphomolybdate.

7. A catalyst as defined in claim 1 wherein said hydrogenating componentis initially admixed with said zeolite base in the form of an insolublecomplex of molybdate or tungstate ions with at least one hydrous oxideof a metal selected from the class consisting of 5 zirconium, titanium,chromium, thorium and iron.

8. A catalyst as defined in claim 1 wherein said hydrogenating componentis initially admixed with said zeolite base in the form of ammoniumheptamolybdate, and wherein a hydrous oxide of zirconium, titanium,chromium, thorium or iron is separately added to the mixture.

9. A catalyst as defined in claim 1 wherein:

2. the pH of said aqueous phase is between about 3 and 5;
 2. A catalystas defined in claim 1 wherein said aqueous phase has a pH between about3 and
 5. 3. A catalyst as defined in claim 1 wherein said zeolite baseis a nickel- or cobalt-stabilized Y zeolite.
 3. the zeolite base is asteam-stabilized hydrogen Y zeolite, a nickel-stabilized Y zeolite, or acobalt-stabilized Y zeolite; and
 4. said Group VIB metal hydrogenatingcomponent is a molybdenum sulfide.
 4. A catalyst as defined in claim 1wherein said zeolite is a steam-stabilized hydrogen Y zeolite.
 5. Acatalyst as defined in claim 1 wherein said hydrogenating component isinitially admixed with said zeolite base in the form of molybdenum oxideand/or tungsten oxide.
 6. A catalyst as defined in claim 1 wherein saidhydrogenating component is initially admixed with said zeolite base inthe form of ammonium heptamolybdate and/or ammonium phosphomolybdaTe. 7.A catalyst as defined in claim 1 wherein said hydrogenating component isinitially admixed with said zeolite base in the form of an insolublecomplex of molybdate or tungstate ions with at least one hydrous oxideof a metal selected from the class consisting of zirconium, titanium,chromium, thorium and iron.
 8. A catalyst as defined in claim 1 whereinsaid hydrogenating component is initially admixed with said zeolite basein the form of ammonium heptamolybdate, and wherein a hydrous oxide ofzirconium, titanium, chromium, thorium or iron is separately added tothe mixture.
 9. A catalyst as defined in claim 1 wherein: